you are blocked by a BitLocker screen on a second-hand laptop because you do not have the password or the recovery key. There is no way to bypass this security measure. BitLocker uses robust encryption designed specifically to lock down a drive completely if it is transferred to a new user without proper authorization. There are no backdoors or software hacks that can circumvent this prompt. Without the previous owner's 48-digit recovery key, the data currently on the drive is permanently encrypted and unrecoverable.
To make the physical computer usable again, you have no choice but to completely wipe the hard drive and start fresh. You will need a second, working computer and a blank USB flash drive with at least 8GB of capacity. Download the Windows 10 Media Creation Tool from the official Microsoft website and follow the prompts to create a bootable installation media on your USB drive. Plug this USB into the locked laptop and boot the machine directly from the USB. This will launch the Windows setup sequence, allowing you to delete all the existing, locked partitions on the internal drive and install a brand-new copy of Windows 10.
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VPHAN